MicroElectroMechanical System (MEMS) devices include microphones and speakers to mention two examples. In the case of a MEMS microphone, sound energy enters through a sound port and vibrates a diaphragm and this action creates a corresponding change in electrical potential (voltage) between the diaphragm and a back plate disposed near the diaphragm. This voltage represents the sound energy that has been received. Typically, the voltage is then transmitted to an integrated circuit (e.g., such as an application specific integrated circuit (ASIC)). Further processing of the signal may be performed on the integrated circuit. For instance, amplification or filtering functions may be performed at the voltage signal at the integrated circuit. MEMS microphones can be used with various customer electronic devices such as those associated with cellular phones or personal computers to mention two examples.
It is typically desired to have the microphone have as great a sensitivity as possible. The greater the sensitivity, the better the performance of the microphone. As is well known, the back volume affects the sensitivity and, generally speaking, the greater the back volume, the greater the sensitivity of the microphone.
As mentioned, MEMS microphones typically have a MEMS device and an integrated circuit (e.g., an application specific integrated circuit (ASIC)) disposed in an assembly. These components, although needed for operation of the microphone, also take up back volume and therefore to some extent limit the amount of sensitivity that can be provided for a particular MEMS device.
Because of these shortcomings, previous approaches have not adequately addressed the above-mentioned problems and user dissatisfaction with these previous approaches has increased.
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